A type of induction heat generation roller device as disclosed in Patent Literature 1 has been proposed, wherein a coolant mist is made to pass through a clearance portion between a roller main body and an induction heat generator that is provided in the roller main body.
In such an induction heat generation roller device, the roller main body is cooled down by the following factors: a latent heat of vaporization which is generated when the coolant mist contacts with an inner surface of the roller and vaporizes; a sensible heat that is generated due to a temperature increase of the coolant mist between the roller main body and the induction heat generator; and a latent heat of vaporization which is generated when the coolant mist vaporizes due to a temperature increase.